1. Field of the Invention
The invention relates to a transparent conductive film, and more particularly to a transparent conductive film formed by an atomic layer deposition process.
2. Description of the Related Art
Generally, transparent conductive films are composed of oxides of at least two elements. The conventional processes for fabricating a mixture of several kinds of oxides to form the transparent conductive film comprise of a sputtering, a radio frequency magnetron sputtering, a direct current (DC) magnetron sputtering, a pulsed laser deposition, or a metal organic chemical vapor deposition process.
However, a temperature above 250° C. is used during the conventional processes to achieve good conductivity for the transparent conductive films. A high processing temperature is not appropriate for substrates made of flexible materials, for example plastic substrates or organic semiconductor materials. Therefore, the above mentioned processes for forming the transparent conductive films cannot be applied to flexible products. Also, fabrication costs for forming the transparent conductive films are high and processes are complicated due to a high vacuum environment requirement and an expensive laser or plasma equipment requirement. Moreover, it is difficult to form large-sized and uniform transparent conductive films by the above mentioned technologies.
Another process for forming the transparent conductive films is an atomic layer deposition process, which can be performed at a low process temperature and a low vacuum environment to form large-sized transparent conductive films.
However, transparent conductive films fabricated by the conventional atomic layer deposition process do not have several kinds of oxides mixed therein uniformly. Specifically, an atomic layer of a first oxide must be first deposited onto a substrate and then another atomic layer of a second oxide must be deposited on the atomic layer of the first oxide and so on, to form stacked atomic layers with all kinds of oxides which achieves a predetermined mixing ratio. Thus, the several kinds of oxides in the stacked multi-layered transparent conductive films fabricated by the conventional atomic layer deposition process are not uniformly mixed, decreasing conductivity thereof.
Therefore, a transparent conductive film which can be fabricated at a low process temperature and a low vacuum environment and a fabrication method thereof to form a large-sized and uniform film which achieves high conductivity are desired.